Every time I press the clutch to shift gears I hear a squealing sound also when I down shift and the gear engages the squealing happens. For example i'm driving in 4th gear I then Press the clutch put it in 3rd and let go of the clutch and then the squealing happens.

 

could be your throw out bearing going

 

I would say its poor lubercation of the release bearing.

 

Or you have a belt slipping. Check the tension on each one.